1. Field of the Invention
This invention relates to a horizontal hotpress system for hot-pressing boards.
2. Description of the Related Art
Regarding a horizontal hotpress system (hotpress) for hot-pressing boards (boards-to-be-processed) such as plywood, decorative sheets and veneers, so as to form them to have a predetermined thickness, the horizontal system is known, which sends a plurality of boards in a standing state between a plurality of hot plates disposed, and hot-presses them by driving at least one of press plates disposed at the both outer sides. This horizontal system (horizontal hotpress) has an advantage of less likely causing unevenness by forming (unevenness of thickness) influenced by the weight of the boards or hot plates themselves, compared to the vertical method (vertical hotpress) which vertically and alternately piles up boards and hot plates held horizontally to be hot-pressed.
Further, this horizontal hotpress generally sends the boards to a press system, having one long side (lower side) of the rectangular boards as a conveying reference plane, and orients the pressing positions of two press cylinders (hydraulic cylinders) disposed in a long side direction of the rectangular boards (horizontally) to a center position of a short side (vertically) of the boards, so as to be hot-pressed. However the size of boards varies nowadays, not only conventionally general so-called 6-shaku boards (approximately 6 feet (1.8 m)×3 feet (0.9 m)), but also so-called 8-shaku (approximately 8 feet (2.4 m)×4 feet (1.2 m)) and so-called 10-shaku (approximately 10 feet (3 m)×5 feet (1.5 m)) are widely available.
As described above, when the size of boards being fed changes, the pressing positions of the press cylinders to the boards change, and inclination of the board increases, so as to possibly result in partial unevenness of the thickness after hot-pressing. Therefore, conventionally according to the size of the board being fed, the pressing positions of the press cylinders have been hitherto controlled to shift (elevated) to the pressing surfaces of the press plates by a control-to-shift feature□e.g. an elevating hydraulic cylinder□so as to prevent the relative pressing positions of the press cylinders to the boards from shifting (Referred to Patent Document 1).